256 Mr. T. R. Jones on North American Entomostraca. 



EXPLANATION OF THE PLATES. 

 Plate IX. 



[From Beechey Island. In the Museum of the Geological Survey of 

 Great Britain.] 



Fig. 1. Beyrichia clathrata; left valve: a, magnified 4 times; 6, magni- 

 fied 24 times. 



Fig. 2. B. plagosa ; left valve : a, magnified 4 times ; b, magnified 24 

 times. 



Fig. 3. Cytheropsis concinna (?) ; right valve : a, magnified 4 times ; 

 b, magnified 24 times. 



Fig. 4. B. rugulifera; right valve: a, magnified 4 times; b, magnified 

 24 times ; c, portion of surface of b, magnified 75 diameters. 



Fig. 5. B. sigillata; left valve: a, magnified 4 times; b, magnified 24 

 times. 



[From Canada. In the Museum of the Geological Survey of Canada.] 

 Fig. 6. B. Logani (var. reniformis) ; magnified 4 times : a, right valve ; 



b, dorsal view ; c, anterior view. From Hawkesbury. 



Fig. 7. B. Logani ; magnified 4 times : a, left valve ; 6, dorsal, and 



c, posterior view. From Hawkesbury. 



Fig. 8. B. Logani ; magnified 4 times : a, left valve ; b, ventral, and 

 c, posterior view. From Grenville. 



Fig. 9. B. Logani ; magnified 4 times : a, right valve ; b, dorsal view. 

 From Hawkesburj'. 



Fig. 10. B. Logani (var. leper ditioides) ; magnified 4 times : «, right valve ; 

 b, anterior view. From Grenville. 



Fig. 11. Leperditia Canadensis ; magnified 4 times : «, left valve; 6, ven- 

 tral, and c, posterior view. From Grenville. 



Fig. 12. L. Canadensis; magnified 4 times: a, right valve; b, ventral 

 view. From Grenville. 



Fig. 13. L. Canadensis (var. labrosa) ; magnified 4 times : a, left valve ; 



b, ventral, and c, anterior view ; d, portion of surface of «, very 

 highly magnified ( X 75). 



Fig. 14. L. Canadensis; magnified 4 times: a, left valve; b, dorsal, and 



c, anterior view. From Grande Isle. 



Fig. 15. L. Canadensis ; dorsal view of the united valves (nearly closed); 

 magnified 4 times. From Grande Isle. 



Fig. 16. L. Canadensis (large variety) : a, right valve, magnified 2 dia- 

 meters ; b, ventral view ; c, anterior view ; d, outline, magnified 

 4 times. From Louck's Mill. 



Fig. 17. L. Canadensis (large var.) : a, right valve, magnified 2 diameters ; 



b, the ventral, and c, the anterior view, showing the inner flange 

 of the ventral edge; d, outline, magnified 4 times. From 

 Pauquctte's Rapids. 



Fig. 18. L.Anna; magnified 4 times: a, right valve; b, ventral, and 



c, anterior view ; c?, portion of surface of «, highly magnified 

 ( X 25). From St. Anne's. 



Plate X. 



[In the Museum of the Geological Survey of Canada.] 



Fig. 1. Isochilina Ottawa; magnified 4 times: a, left valve; b, anterior, 

 and c, ventral view. From Grenville Canal. 



